#include <iostream>
using namespace std;

#define CLK_TCK 100

signed main()
{
	int c1,c2;
	cin>>c1>>c2;
	int c=c2-c1;
	if(c%CLK_TCK>=CLK_TCK/2)c+=CLK_TCK;
	c /= CLK_TCK;
	int s = c%60,m = c/60%60,h = c/60/60;
	printf("%02d:%02d:%02d",h,m,s);
	return 0;
 } 
